/*****************************************************************************
* lcp.c - Network Link Control Protocol program file.
*
* Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
* portions Copyright (c) 1997 by Global Election Systems Inc.
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice and the following disclaimer are included verbatim in any
* distributions. No written agreement, license, or royalty fee is required
* for any of the authorized uses.
*
* THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
******************************************************************************
* REVISION HISTORY
*
* 03-01-01 Marc Boucher <marc@mbsi.ca>
*   Ported to lwIP.
* 97-12-01 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
*	Original.
*****************************************************************************/

/*
 * lcp.c - PPP Link Control Protocol.
 *
 * Copyright (c) 1989 Carnegie Mellon University.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by Carnegie Mellon University.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <string.h>

#include "ppp.h"
#if PPP_SUPPORT > 0
#include "fsm.h"
#include "chap.h"
#include "magic.h"
#include "auth.h"
#include "lcp.h"
#include "pppdebug.h"


/*************************/
/*** LOCAL DEFINITIONS ***/
/*************************/
/*
 * Length of each type of configuration option (in octets)
 */
#define CILEN_VOID	2
#define CILEN_CHAR	3
#define CILEN_SHORT	4	/* CILEN_VOID + sizeof(short) */
#define CILEN_CHAP	5	/* CILEN_VOID + sizeof(short) + 1 */
#define CILEN_LONG	6	/* CILEN_VOID + sizeof(long) */
#define CILEN_LQR	8	/* CILEN_VOID + sizeof(short) + sizeof(long) */
#define CILEN_CBCP	3


/***********************************/
/*** LOCAL FUNCTION DECLARATIONS ***/
/***********************************/
/*
 * Callbacks for fsm code.  (CI = Configuration Information)
 */
static void lcp_resetci (fsm*);	        /* Reset our CI */
static int  lcp_cilen (fsm*);		        /* Return length of our CI */
static void lcp_addci (fsm*, u_char*, int*);       /* Add our CI to pkt */
static int  lcp_ackci (fsm*, u_char*, int);/* Peer ack'd our CI */
static int  lcp_nakci (fsm*, u_char*, int);/* Peer nak'd our CI */
static int  lcp_rejci (fsm*, u_char*, int);/* Peer rej'd our CI */
static int  lcp_reqci (fsm*, u_char*, int*, int);  /* Rcv peer CI */
static void lcp_up (fsm*);		            /* We're UP */
static void lcp_down (fsm*);	    	    /* We're DOWN */
static void lcp_starting (fsm*);   	    /* We need lower layer up */
static void lcp_finished (fsm*);	        /* We need lower layer down */
static int  lcp_extcode (fsm*, int, u_char, u_char*, int);

static void lcp_rprotrej (fsm*, u_char*, int);

/*
 * routines to send LCP echos to peer
 */
static void lcp_echo_lowerup (int);
static void lcp_echo_lowerdown (int);
static void LcpEchoTimeout (void*);
static void lcp_received_echo_reply (fsm*, int, u_char*, int);
static void LcpSendEchoRequest (fsm*);
static void LcpLinkFailure (fsm*);
static void LcpEchoCheck (fsm*);

/*
 * Protocol entry points.
 * Some of these are called directly.
 */
static void lcp_input (int, u_char *, int);
static void lcp_protrej (int);

#define CODENAME(x)	((x) == CONFACK ? "ACK" : \
			 (x) == CONFNAK ? "NAK" : "REJ")


/******************************/
/*** PUBLIC DATA STRUCTURES ***/
/******************************/
/* global vars */
LinkPhase lcp_phase[NUM_PPP];			/* Phase of link session (RFC 1661) */
lcp_options lcp_wantoptions[NUM_PPP];	/* Options that we want to request */
lcp_options lcp_gotoptions[NUM_PPP];	/* Options that peer ack'd */
lcp_options lcp_allowoptions[NUM_PPP];	/* Options we allow peer to request */
lcp_options lcp_hisoptions[NUM_PPP];	/* Options that we ack'd */
ext_accm xmit_accm[NUM_PPP];			/* extended transmit ACCM */



/*****************************/
/*** LOCAL DATA STRUCTURES ***/
/*****************************/
static fsm lcp_fsm[NUM_PPP];			/* LCP fsm structure (global)*/
static u_int	 lcp_echo_interval = LCP_ECHOINTERVAL; /* Interval between LCP echo-requests */
static u_int	 lcp_echo_fails = LCP_MAXECHOFAILS; /* Tolerance to unanswered echo-requests */
static u32_t lcp_echos_pending = 0;	/* Number of outstanding echo msgs */
static u32_t lcp_echo_number   = 0;	/* ID number of next echo frame */
static u32_t lcp_echo_timer_running = 0;  /* TRUE if a timer is running */

static u_char nak_buffer[PPP_MRU];	/* where we construct a nak packet */

static fsm_callbacks lcp_callbacks =
        {	/* LCP callback routines */
                lcp_resetci,		/* Reset our Configuration Information */
                lcp_cilen,			/* Length of our Configuration Information */
                lcp_addci,			/* Add our Configuration Information */
                lcp_ackci,			/* ACK our Configuration Information */
                lcp_nakci,			/* NAK our Configuration Information */
                lcp_rejci,			/* Reject our Configuration Information */
                lcp_reqci,			/* Request peer's Configuration Information */
                lcp_up,				/* Called when fsm reaches OPENED state */
                lcp_down,			/* Called when fsm leaves OPENED state */
                lcp_starting,		/* Called when we want the lower layer up */
                lcp_finished,		/* Called when we want the lower layer down */
                NULL,				/* Called when Protocol-Reject received */
                NULL,				/* Retransmission is necessary */
                lcp_extcode,		/* Called to handle LCP-specific codes */
                "LCP"				/* String name of protocol */
        };

struct protent lcp_protent =
        {
                PPP_LCP,
                lcp_init,
                lcp_input,
                lcp_protrej,
                lcp_lowerup,
                lcp_lowerdown,
                lcp_open,
                lcp_close,
#if 0
                lcp_printpkt,
                NULL,
#endif
                1,
                "LCP",
#if 0
                NULL,
                NULL,
                NULL
#endif
        };

int lcp_loopbackfail = DEFLOOPBACKFAIL;



/***********************************/
/*** PUBLIC FUNCTION DEFINITIONS ***/
/***********************************/
/*
 * lcp_init - Initialize LCP.
 */
void lcp_init(int unit)
{
        fsm *f = &lcp_fsm[unit];
        lcp_options *wo = &lcp_wantoptions[unit];
        lcp_options *ao = &lcp_allowoptions[unit];

        f->unit = unit;
        f->protocol = PPP_LCP;
        f->callbacks = &lcp_callbacks;

        fsm_init(f);

        wo->passive = 0;
        wo->silent = 0;
        wo->restart = 0;			/* Set to 1 in kernels or multi-line
        								 * implementations */
        wo->neg_mru = 1;
        wo->mru = PPP_DEFMRU;
        wo->neg_asyncmap = 1;
        wo->asyncmap = 0x00000000l;	/* Assume don't need to escape any ctl chars. */
        wo->neg_chap = 0;			/* Set to 1 on server */
        wo->neg_upap = 0;			/* Set to 1 on server */
        wo->chap_mdtype = CHAP_DIGEST_MD5;
        wo->neg_magicnumber = 1;
        wo->neg_pcompression = 1;
        wo->neg_accompression = 1;
        wo->neg_lqr = 0;			/* no LQR implementation yet */
        wo->neg_cbcp = 0;

        ao->neg_mru = 1;
        ao->mru = PPP_MAXMRU;
        ao->neg_asyncmap = 1;
        ao->asyncmap = 0x00000000l;	/* Assume don't need to escape any ctl chars. */
        ao->neg_chap = (CHAP_SUPPORT != 0);
        ao->chap_mdtype = CHAP_DIGEST_MD5;
        ao->neg_upap = (PAP_SUPPORT != 0);
        ao->neg_magicnumber = 1;
        ao->neg_pcompression = 1;
        ao->neg_accompression = 1;
        ao->neg_lqr = 0;			/* no LQR implementation yet */
        ao->neg_cbcp = (CBCP_SUPPORT != 0);

        /*
         * Set transmit escape for the flag and escape characters plus anything
         * set for the allowable options.
         */
        memset(xmit_accm[unit], 0, sizeof(xmit_accm[0]));
        xmit_accm[unit][15] = 0x60;
        xmit_accm[unit][0] = (u_char)(ao->asyncmap & 0xFF);
        xmit_accm[unit][1] = (u_char)((ao->asyncmap >> 8) & 0xFF);
        xmit_accm[unit][2] = (u_char)((ao->asyncmap >> 16) & 0xFF);
        xmit_accm[unit][3] = (u_char)((ao->asyncmap >> 24) & 0xFF);
        LCPDEBUG((LOG_INFO, "lcp_init: xmit_accm=%X %X %X %X\n",
                  xmit_accm[unit][0],
                  xmit_accm[unit][1],
                  xmit_accm[unit][2],
                  xmit_accm[unit][3]));

        lcp_phase[unit] = PHASE_INITIALIZE;
}


/*
 * lcp_open - LCP is allowed to come up.
 */
void lcp_open(int unit)
{
        fsm *f = &lcp_fsm[unit];
        lcp_options *wo = &lcp_wantoptions[unit];

        f->flags = 0;
        if (wo->passive)
                f->flags |= OPT_PASSIVE;
        if (wo->silent)
                f->flags |= OPT_SILENT;
        fsm_open(f);

        lcp_phase[unit] = PHASE_ESTABLISH;
}


/*
 * lcp_close - Take LCP down.
 */
void lcp_close(int unit, char *reason)
{
        fsm *f = &lcp_fsm[unit];

        if (lcp_phase[unit] != PHASE_DEAD)
                lcp_phase[unit] = PHASE_TERMINATE;
        if (f->state == STOPPED && f->flags & (OPT_PASSIVE|OPT_SILENT)) {
                /*
                 * This action is not strictly according to the FSM in RFC1548,
                 * but it does mean that the program terminates if you do an
                 * lcp_close() in passive/silent mode when a connection hasn't
                 * been established.
                 */
                f->state = CLOSED;
                lcp_finished(f);
        } else
                fsm_close(&lcp_fsm[unit], reason);
}


/*
 * lcp_lowerup - The lower layer is up.
 */
void lcp_lowerup(int unit)
{
        lcp_options *wo = &lcp_wantoptions[unit];

        /*
        * Don't use A/C or protocol compression on transmission,
        * but accept A/C and protocol compressed packets
        * if we are going to ask for A/C and protocol compression.
        */
        ppp_set_xaccm(unit, &xmit_accm[unit]);
        ppp_send_config(unit, PPP_MRU, 0xffffffffl, 0, 0);
        ppp_recv_config(unit, PPP_MRU, 0x00000000l,
                        wo->neg_pcompression, wo->neg_accompression);
        peer_mru[unit] = PPP_MRU;
        lcp_allowoptions[unit].asyncmap
        = (u_long)xmit_accm[unit][0]
          | ((u_long)xmit_accm[unit][1] << 8)
          | ((u_long)xmit_accm[unit][2] << 16)
          | ((u_long)xmit_accm[unit][3] << 24);
        LCPDEBUG((LOG_INFO, "lcp_lowerup: asyncmap=%X %X %X %X\n",
                  xmit_accm[unit][3],
                  xmit_accm[unit][2],
                  xmit_accm[unit][1],
                  xmit_accm[unit][0]));

        fsm_lowerup(&lcp_fsm[unit]);
}


/*
 * lcp_lowerdown - The lower layer is down.
 */
void lcp_lowerdown(int unit)
{
        fsm_lowerdown(&lcp_fsm[unit]);
}

/*
 * lcp_sprotrej - Send a Protocol-Reject for some protocol.
 */
void lcp_sprotrej(int unit, u_char *p, int len)
{
        /*
        * Send back the protocol and the information field of the
        * rejected packet.  We only get here if LCP is in the OPENED state.
        */

        fsm_sdata(&lcp_fsm[unit], PROTREJ, ++lcp_fsm[unit].id,
                  p, len);
}



/**********************************/
/*** LOCAL FUNCTION DEFINITIONS ***/
/**********************************/
/*
 * lcp_input - Input LCP packet.
 */
static void lcp_input(int unit, u_char *p, int len)
{
        fsm *f = &lcp_fsm[unit];

        fsm_input(f, p, len);
}


/*
 * lcp_extcode - Handle a LCP-specific code.
 */
static int lcp_extcode(fsm *f, int code, u_char id, u_char *inp, int len)
{
        u_char *magp;

        switch ( code ) {
        case PROTREJ:
                lcp_rprotrej(f, inp, len);
                break;

        case ECHOREQ:
                if (f->state != OPENED)
                        break;
                LCPDEBUG((LOG_INFO, "lcp: Echo-Request, Rcvd id %d\n", id));
                magp = inp;
                PUTLONG(lcp_gotoptions[f->unit].magicnumber, magp);
                fsm_sdata(f, ECHOREP, id, inp, len);
                break;

        case ECHOREP:
                lcp_received_echo_reply(f, id, inp, len);
                break;

        case DISCREQ:
                break;

        default:
                return 0;
        }
        return 1;
}


/*
 * lcp_rprotrej - Receive an Protocol-Reject.
 *
 * Figure out which protocol is rejected and inform it.
 */
static void lcp_rprotrej(fsm *f, u_char *inp, int len)
{
        int i;
        struct protent *protp;
        u_short prot;

        if (len < sizeof (u_short)) {
                LCPDEBUG((LOG_INFO,
                          "lcp_rprotrej: Rcvd short Protocol-Reject packet!\n"));
                return;
        }

        GETSHORT(prot, inp);

        LCPDEBUG((LOG_INFO,
                  "lcp_rprotrej: Rcvd Protocol-Reject packet for %x!\n",
                  prot));

        /*
        * Protocol-Reject packets received in any state other than the LCP
        * OPENED state SHOULD be silently discarded.
        */
        if ( f->state != OPENED ) {
                LCPDEBUG((LOG_INFO, "Protocol-Reject discarded: LCP in state %d\n",
                          f->state));
                return;
        }

        /*
        * Upcall the proper Protocol-Reject routine.
        */
        for (i = 0; (protp = ppp_protocols[i]) != NULL; ++i)
                if (protp->protocol == prot && protp->enabled_flag) {
                        (*protp->protrej)(f->unit);
                        return;
                }

        LCPDEBUG((LOG_WARNING, "Protocol-Reject for unsupported protocol 0x%x\n",
                  prot));
}


/*
 * lcp_protrej - A Protocol-Reject was received.
 */
static void lcp_protrej(int unit)
{
        (void)unit;
        /*
        * Can't reject LCP!
        */
        LCPDEBUG((LOG_WARNING,
                  "lcp_protrej: Received Protocol-Reject for LCP!\n"));
        fsm_protreject(&lcp_fsm[unit]);
}


/*
 * lcp_resetci - Reset our CI.
 */
static void lcp_resetci(fsm *f)
{
        lcp_wantoptions[f->unit].magicnumber = magic();
        lcp_wantoptions[f->unit].numloops = 0;
        lcp_gotoptions[f->unit] = lcp_wantoptions[f->unit];
        peer_mru[f->unit] = PPP_MRU;
        auth_reset(f->unit);
}


/*
 * lcp_cilen - Return length of our CI.
 */
static int lcp_cilen(fsm *f)
{
        lcp_options *go = &lcp_gotoptions[f->unit];

#define LENCIVOID(neg)	((neg) ? CILEN_VOID : 0)
#define LENCICHAP(neg)	((neg) ? CILEN_CHAP : 0)
#define LENCISHORT(neg)	((neg) ? CILEN_SHORT : 0)
#define LENCILONG(neg)	((neg) ? CILEN_LONG : 0)
#define LENCILQR(neg)	((neg) ? CILEN_LQR: 0)
#define LENCICBCP(neg)	((neg) ? CILEN_CBCP: 0)
        /*
        * NB: we only ask for one of CHAP and UPAP, even if we will
        * accept either.
        */
        return (LENCISHORT(go->neg_mru && go->mru != PPP_DEFMRU) +
                LENCILONG(go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl) +
                LENCICHAP(go->neg_chap) +
                LENCISHORT(!go->neg_chap && go->neg_upap) +
                LENCILQR(go->neg_lqr) +
                LENCICBCP(go->neg_cbcp) +
                LENCILONG(go->neg_magicnumber) +
                LENCIVOID(go->neg_pcompression) +
                LENCIVOID(go->neg_accompression));
}


/*
 * lcp_addci - Add our desired CIs to a packet.
 */
static void lcp_addci(fsm *f, u_char *ucp, int *lenp)
{
        lcp_options *go = &lcp_gotoptions[f->unit];
        u_char *start_ucp = ucp;

#define ADDCIVOID(opt, neg) \
	if (neg) { \
	    LCPDEBUG((LOG_INFO, "lcp_addci: opt=%d\n", opt)); \
		PUTCHAR(opt, ucp); \
		PUTCHAR(CILEN_VOID, ucp); \
	}
#define ADDCISHORT(opt, neg, val) \
	if (neg) { \
	    LCPDEBUG((LOG_INFO, "lcp_addci: INT opt=%d %X\n", opt, val)); \
		PUTCHAR(opt, ucp); \
		PUTCHAR(CILEN_SHORT, ucp); \
		PUTSHORT(val, ucp); \
	}
#define ADDCICHAP(opt, neg, val, digest) \
	if (neg) { \
	    LCPDEBUG((LOG_INFO, "lcp_addci: CHAP opt=%d %X\n", opt, val)); \
		PUTCHAR(opt, ucp); \
		PUTCHAR(CILEN_CHAP, ucp); \
		PUTSHORT(val, ucp); \
		PUTCHAR(digest, ucp); \
	}
#define ADDCILONG(opt, neg, val) \
	if (neg) { \
	    LCPDEBUG((LOG_INFO, "lcp_addci: L opt=%d %lX\n", opt, val)); \
		PUTCHAR(opt, ucp); \
		PUTCHAR(CILEN_LONG, ucp); \
		PUTLONG(val, ucp); \
	}
#define ADDCILQR(opt, neg, val) \
	if (neg) { \
	    LCPDEBUG((LOG_INFO, "lcp_addci: LQR opt=%d %lX\n", opt, val)); \
		PUTCHAR(opt, ucp); \
		PUTCHAR(CILEN_LQR, ucp); \
		PUTSHORT(PPP_LQR, ucp); \
		PUTLONG(val, ucp); \
	}
#define ADDCICHAR(opt, neg, val) \
	if (neg) { \
	    LCPDEBUG((LOG_INFO, "lcp_addci: CHAR opt=%d %X '%z'\n", opt, val, val)); \
		PUTCHAR(opt, ucp); \
		PUTCHAR(CILEN_CHAR, ucp); \
		PUTCHAR(val, ucp); \
	}

        ADDCISHORT(CI_MRU, go->neg_mru && go->mru != PPP_DEFMRU, go->mru);
        ADDCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl,
                  go->asyncmap);
        ADDCICHAP(CI_AUTHTYPE, go->neg_chap, PPP_CHAP, go->chap_mdtype);
        ADDCISHORT(CI_AUTHTYPE, !go->neg_chap && go->neg_upap, PPP_PAP);
        ADDCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
        ADDCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
        ADDCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
        ADDCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
        ADDCIVOID(CI_ACCOMPRESSION, go->neg_accompression);

        if (ucp - start_ucp != *lenp) {
                /* this should never happen, because peer_mtu should be 1500 */
                LCPDEBUG((LOG_ERR, "Bug in lcp_addci: wrong length\n"));
        }
}


/*
 * lcp_ackci - Ack our CIs.
 * This should not modify any state if the Ack is bad.
 *
 * Returns:
 *	0 - Ack was bad.
 *	1 - Ack was good.
 */
static int lcp_ackci(fsm *f, u_char *p, int len)
{
        lcp_options *go = &lcp_gotoptions[f->unit];
        u_char cilen, citype, cichar;
        u_short cishort;
        u32_t cilong;

        /*
        * CIs must be in exactly the same order that we sent.
        * Check packet length and CI length at each step.
        * If we find any deviations, then this packet is bad.
        */
#define ACKCIVOID(opt, neg) \
	if (neg) { \
		if ((len -= CILEN_VOID) < 0) \
			goto bad; \
		GETCHAR(citype, p); \
		GETCHAR(cilen, p); \
		if (cilen != CILEN_VOID || \
				citype != opt) \
			goto bad; \
	}
#define ACKCISHORT(opt, neg, val) \
	if (neg) { \
		if ((len -= CILEN_SHORT) < 0) \
			goto bad; \
		GETCHAR(citype, p); \
		GETCHAR(cilen, p); \
		if (cilen != CILEN_SHORT || \
				citype != opt) \
			goto bad; \
		GETSHORT(cishort, p); \
		if (cishort != val) \
			goto bad; \
	}
#define ACKCICHAR(opt, neg, val) \
	if (neg) { \
		if ((len -= CILEN_CHAR) < 0) \
			goto bad; \
		GETCHAR(citype, p); \
		GETCHAR(cilen, p); \
		if (cilen != CILEN_CHAR || \
				citype != opt) \
			goto bad; \
		GETCHAR(cichar, p); \
		if (cichar != val) \
			goto bad; \
	}
#define ACKCICHAP(opt, neg, val, digest) \
	if (neg) { \
		if ((len -= CILEN_CHAP) < 0) \
			goto bad; \
		GETCHAR(citype, p); \
		GETCHAR(cilen, p); \
		if (cilen != CILEN_CHAP || \
				citype != opt) \
			goto bad; \
		GETSHORT(cishort, p); \
		if (cishort != val) \
			goto bad; \
		GETCHAR(cichar, p); \
		if (cichar != digest) \
			goto bad; \
	}
#define ACKCILONG(opt, neg, val) \
	if (neg) { \
		if ((len -= CILEN_LONG) < 0) \
			goto bad; \
		GETCHAR(citype, p); \
		GETCHAR(cilen, p); \
		if (cilen != CILEN_LONG || \
				citype != opt) \
			goto bad; \
		GETLONG(cilong, p); \
		if (cilong != val) \
			goto bad; \
	}
#define ACKCILQR(opt, neg, val) \
	if (neg) { \
		if ((len -= CILEN_LQR) < 0) \
			goto bad; \
		GETCHAR(citype, p); \
		GETCHAR(cilen, p); \
		if (cilen != CILEN_LQR || \
				citype != opt) \
			goto bad; \
		GETSHORT(cishort, p); \
		if (cishort != PPP_LQR) \
			goto bad; \
		GETLONG(cilong, p); \
		if (cilong != val) \
			goto bad; \
	}

        ACKCISHORT(CI_MRU, go->neg_mru && go->mru != PPP_DEFMRU, go->mru);
        ACKCILONG(CI_ASYNCMAP, go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl,
                  go->asyncmap);
        ACKCICHAP(CI_AUTHTYPE, go->neg_chap, PPP_CHAP, go->chap_mdtype);
        ACKCISHORT(CI_AUTHTYPE, !go->neg_chap && go->neg_upap, PPP_PAP);
        ACKCILQR(CI_QUALITY, go->neg_lqr, go->lqr_period);
        ACKCICHAR(CI_CALLBACK, go->neg_cbcp, CBCP_OPT);
        ACKCILONG(CI_MAGICNUMBER, go->neg_magicnumber, go->magicnumber);
        ACKCIVOID(CI_PCOMPRESSION, go->neg_pcompression);
        ACKCIVOID(CI_ACCOMPRESSION, go->neg_accompression);

        /*
         * If there are any remaining CIs, then this packet is bad.
         */
        if (len != 0)
                goto bad;
        LCPDEBUG((LOG_INFO, "lcp_acki: Ack\n"));
        return (1);
bad:
        LCPDEBUG((LOG_WARNING, "lcp_acki: received bad Ack!\n"));
        return (0);
}


/*
 * lcp_nakci - Peer has sent a NAK for some of our CIs.
 * This should not modify any state if the Nak is bad
 * or if LCP is in the OPENED state.
 *
 * Returns:
 *	0 - Nak was bad.
 *	1 - Nak was good.
 */
static int lcp_nakci(fsm *f, u_char *p, int len)
{
        lcp_options *go = &lcp_gotoptions[f->unit];
        lcp_options *wo = &lcp_wantoptions[f->unit];
        u_char citype, cichar, *next;
        u_short cishort;
        u32_t cilong;
        lcp_options no;		/* options we've seen Naks for */
        lcp_options try;		/* options to request next time */
        int looped_back = 0;
        int cilen;

        BZERO(&no, sizeof(no));
        try = *go;

        /*
        * Any Nak'd CIs must be in exactly the same order that we sent.
        * Check packet length and CI length at each step.
        * If we find any deviations, then this packet is bad.
        */
#define NAKCIVOID(opt, neg, code) \
	if (go->neg && \
			len >= CILEN_VOID && \
			p[1] == CILEN_VOID && \
			p[0] == opt) { \
		len -= CILEN_VOID; \
		INCPTR(CILEN_VOID, p); \
		no.neg = 1; \
		code \
	}
#define NAKCICHAP(opt, neg, code) \
	if (go->neg && \
			len >= CILEN_CHAP && \
			p[1] == CILEN_CHAP && \
			p[0] == opt) { \
		len -= CILEN_CHAP; \
		INCPTR(2, p); \
		GETSHORT(cishort, p); \
		GETCHAR(cichar, p); \
		no.neg = 1; \
		code \
	}
#define NAKCICHAR(opt, neg, code) \
	if (go->neg && \
			len >= CILEN_CHAR && \
			p[1] == CILEN_CHAR && \
			p[0] == opt) { \
		len -= CILEN_CHAR; \
		INCPTR(2, p); \
		GETCHAR(cichar, p); \
		no.neg = 1; \
		code \
	}
#define NAKCISHORT(opt, neg, code) \
	if (go->neg && \
			len >= CILEN_SHORT && \
			p[1] == CILEN_SHORT && \
			p[0] == opt) { \
		len -= CILEN_SHORT; \
		INCPTR(2, p); \
		GETSHORT(cishort, p); \
		no.neg = 1; \
		code \
	}
#define NAKCILONG(opt, neg, code) \
	if (go->neg && \
			len >= CILEN_LONG && \
			p[1] == CILEN_LONG && \
			p[0] == opt) { \
		len -= CILEN_LONG; \
		INCPTR(2, p); \
		GETLONG(cilong, p); \
		no.neg = 1; \
		code \
	}
#define NAKCILQR(opt, neg, code) \
	if (go->neg && \
			len >= CILEN_LQR && \
			p[1] == CILEN_LQR && \
			p[0] == opt) { \
		len -= CILEN_LQR; \
		INCPTR(2, p); \
		GETSHORT(cishort, p); \
		GETLONG(cilong, p); \
		no.neg = 1; \
		code \
	}

        /*
        * We don't care if they want to send us smaller packets than
        * we want.  Therefore, accept any MRU less than what we asked for,
        * but then ignore the new value when setting the MRU in the kernel.
        * If they send us a bigger MRU than what we asked, accept it, up to
        * the limit of the default MRU we'd get if we didn't negotiate.
        */
        if (go->neg_mru && go->mru != PPP_DEFMRU) {
                NAKCISHORT(CI_MRU, neg_mru,
                           if (cishort <= wo->mru || cishort < PPP_DEFMRU)
                           try.mru = cishort;
                          );
        }

        /*
        * Add any characters they want to our (receive-side) asyncmap.
        */
        if (go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl) {
                NAKCILONG(CI_ASYNCMAP, neg_asyncmap,
                          try.asyncmap = go->asyncmap | cilong;
                         );
        }

        /*
        * If they've nak'd our authentication-protocol, check whether
        * they are proposing a different protocol, or a different
        * hash algorithm for CHAP.
        */
        if ((go->neg_chap || go->neg_upap)
                        && len >= CILEN_SHORT
                        && p[0] == CI_AUTHTYPE && p[1] >= CILEN_SHORT && p[1] <= len) {
                cilen = p[1];
                len -= cilen;
                no.neg_chap = go->neg_chap;
                no.neg_upap = go->neg_upap;
                INCPTR(2, p);
                GETSHORT(cishort, p);
                if (cishort == PPP_PAP && cilen == CILEN_SHORT) {
                        /*
                         * If we were asking for CHAP, they obviously don't want to do it.
                         * If we weren't asking for CHAP, then we were asking for PAP,
                         * in which case this Nak is bad.
                         */
                        if (!go->neg_chap)
                                goto bad;
                        try.neg_chap = 0;

                } else if (cishort == PPP_CHAP && cilen == CILEN_CHAP) {
                        GETCHAR(cichar, p);
                        if (go->neg_chap) {
                                /*
                                 * We were asking for CHAP/MD5; they must want a different
                                 * algorithm.  If they can't do MD5, we'll have to stop
                                 * asking for CHAP.
                                 */
                                if (cichar != go->chap_mdtype)
                                        try.neg_chap = 0;
                        } else {
                                /*
                                 * Stop asking for PAP if we were asking for it.
                                 */
                                try.neg_upap = 0;
                        }

                } else {
                        /*
                         * We don't recognize what they're suggesting.
                         * Stop asking for what we were asking for.
                         */
                        if (go->neg_chap)
                                try.neg_chap = 0;
                        else
                                try.neg_upap = 0;
                        p += cilen - CILEN_SHORT;
                }
        }

        /*
        * If they can't cope with our link quality protocol, we'll have
        * to stop asking for LQR.  We haven't got any other protocol.
        * If they Nak the reporting period, take their value XXX ?
        */
        NAKCILQR(CI_QUALITY, neg_lqr,
                 if (cishort != PPP_LQR)
                 try.neg_lqr = 0;
                 else
                         try.lqr_period = cilong;
                        );

        /*
        * Only implementing CBCP...not the rest of the callback options
        */
        NAKCICHAR(CI_CALLBACK, neg_cbcp,
                  try.neg_cbcp = 0;
                 );

        /*
        * Check for a looped-back line.
        */
        NAKCILONG(CI_MAGICNUMBER, neg_magicnumber,
                  try.magicnumber = magic();
                  looped_back = 1;
                 );

        /*
        * Peer shouldn't send Nak for protocol compression or
        * address/control compression requests; they should send
        * a Reject instead.  If they send a Nak, treat it as a Reject.
        */
        NAKCIVOID(CI_PCOMPRESSION, neg_pcompression,
                  try.neg_pcompression = 0;
                 );
        NAKCIVOID(CI_ACCOMPRESSION, neg_accompression,
                  try.neg_accompression = 0;
                 );

        /*
        * There may be remaining CIs, if the peer is requesting negotiation
        * on an option that we didn't include in our request packet.
        * If we see an option that we requested, or one we've already seen
        * in this packet, then this packet is bad.
        * If we wanted to respond by starting to negotiate on the requested
        * option(s), we could, but we don't, because except for the
        * authentication type and quality protocol, if we are not negotiating
        * an option, it is because we were told not to.
        * For the authentication type, the Nak from the peer means
        * `let me authenticate myself with you' which is a bit pointless.
        * For the quality protocol, the Nak means `ask me to send you quality
        * reports', but if we didn't ask for them, we don't want them.
        * An option we don't recognize represents the peer asking to
        * negotiate some option we don't support, so ignore it.
        */
        while (len > CILEN_VOID) {
                GETCHAR(citype, p);
                GETCHAR(cilen, p);
                if (cilen < CILEN_VOID || (len -= cilen) < 0)
                        goto bad;
                next = p + cilen - 2;

                switch (citype) {
                case CI_MRU:
                        if ((go->neg_mru && go->mru != PPP_DEFMRU)
                                        || no.neg_mru || cilen != CILEN_SHORT)
                                goto bad;
                        GETSHORT(cishort, p);
                        if (cishort < PPP_DEFMRU)
                                try.mru = cishort;
                        break;
                case CI_ASYNCMAP:
                        if ((go->neg_asyncmap && go->asyncmap != 0xFFFFFFFFl)
                                        || no.neg_asyncmap || cilen != CILEN_LONG)
                                goto bad;
                        break;
                case CI_AUTHTYPE:
                        if (go->neg_chap || no.neg_chap || go->neg_upap || no.neg_upap)
                                goto bad;
                        break;
                case CI_MAGICNUMBER:
                        if (go->neg_magicnumber || no.neg_magicnumber ||
                                        cilen != CILEN_LONG)
                                goto bad;
                        break;
                case CI_PCOMPRESSION:
                        if (go->neg_pcompression || no.neg_pcompression
                                        || cilen != CILEN_VOID)
                                goto bad;
                        break;
                case CI_ACCOMPRESSION:
                        if (go->neg_accompression || no.neg_accompression
                                        || cilen != CILEN_VOID)
                                goto bad;
                        break;
                case CI_QUALITY:
                        if (go->neg_lqr || no.neg_lqr || cilen != CILEN_LQR)
                                goto bad;
                        break;
                }
                p = next;
        }

        /* If there is still anything left, this packet is bad. */
        if (len != 0)
                goto bad;

        /*
        * OK, the Nak is good.  Now we can update state.
        */
        if (f->state != OPENED) {
                if (looped_back) {
                        if (++try.numloops >= lcp_loopbackfail) {
                                LCPDEBUG((LOG_NOTICE, "Serial line is looped back.\n"));
                                lcp_close(f->unit, "Loopback detected");
                        }
                } else
                        try.numloops = 0;
                *go = try;
        }

        return 1;

bad:
        LCPDEBUG((LOG_WARNING, "lcp_nakci: received bad Nak!\n"));
        return 0;
}


/*
 * lcp_rejci - Peer has Rejected some of our CIs.
 * This should not modify any state if the Reject is bad
 * or if LCP is in the OPENED state.
 *
 * Returns:
 *	0 - Reject was bad.
 *	1 - Reject was good.
 */
static int lcp_rejci(fsm *f, u_char *p, int len)
{
        lcp_options *go = &lcp_gotoptions[f->unit];
        u_char cichar;
        u_short cishort;
        u32_t cilong;
        lcp_options try;		/* options to request next time */

        try = *go;

        /*
        * Any Rejected CIs must be in exactly the same order that we sent.
        * Check packet length and CI length at each step.
        * If we find any deviations, then this packet is bad.
        */
#define REJCIVOID(opt, neg) \
	if (go->neg && \
			len >= CILEN_VOID && \
			p[1] == CILEN_VOID && \
			p[0] == opt) { \
		len -= CILEN_VOID; \
		INCPTR(CILEN_VOID, p); \
		try.neg = 0; \
		LCPDEBUG((LOG_INFO, "lcp_rejci: void opt %d rejected\n", opt)); \
	}
#define REJCISHORT(opt, neg, val) \
	if (go->neg && \
			len >= CILEN_SHORT && \
			p[1] == CILEN_SHORT && \
			p[0] == opt) { \
		len -= CILEN_SHORT; \
		INCPTR(2, p); \
		GETSHORT(cishort, p); \
		/* Check rejected value. */ \
		if (cishort != val) \
			goto bad; \
		try.neg = 0; \
		LCPDEBUG((LOG_INFO,"lcp_rejci: short opt %d rejected\n", opt)); \
	}
#define REJCICHAP(opt, neg, val, digest) \
	if (go->neg && \
			len >= CILEN_CHAP && \
			p[1] == CILEN_CHAP && \
			p[0] == opt) { \
		len -= CILEN_CHAP; \
		INCPTR(2, p); \
		GETSHORT(cishort, p); \
		GETCHAR(cichar, p); \
		/* Check rejected value. */ \
		if (cishort != val || cichar != digest) \
			goto bad; \
		try.neg = 0; \
		try.neg_upap = 0; \
		LCPDEBUG((LOG_INFO,"lcp_rejci: chap opt %d rejected\n", opt)); \
	}
#define REJCILONG(opt, neg, val) \
	if (go->neg && \
			len >= CILEN_LONG && \
			p[1] == CILEN_LONG && \
			p[0] == opt) { \
		len -= CILEN_LONG; \
		INCPTR(2, p); \
		GETLONG(cilong, p); \
		/* Check rejected value. */ \
		if (cilong != val) \
			goto bad; \
		try.neg = 0; \
		LCPDEBUG((LOG_INFO,"lcp_rejci: long opt %d rejected\n", opt)); \
	}
#define REJCILQR(opt, neg, val) \
	if (go->neg && \
			len >= CILEN_LQR && \
			p[1] == CILEN_LQR && \
			p[0] == opt) { \
		len -= CILEN_LQR; \
		INCPTR(2, p); \
		GETSHORT(cishort, p); \
		GETLONG(cilong, p); \
		/* Check rejected value. */ \
		if (cishort != PPP_LQR || cilong != val) \
			goto bad; \
		try.neg = 0; \
		LCPDEBUG((LOG_INFO,"lcp_rejci: LQR opt %d rejected\n", opt)); \
	}
#define REJCICBCP(opt, neg, val) \
	if (go->neg && \
			len >= CILEN_CBCP && \
			p[1] == CILEN_CBCP && \
			p[0] == opt) { \
		len -= CILEN_CBCP; \
		INCPTR(2, p); \
		GETCHAR(cichar, p); \
		/* Check rejected value. */ \
		if (cichar != val) \
			goto bad; \
		try.neg = 0; \
		LCPDEBUG((LOG_INFO,"lcp_rejci: Callback opt %d rejected\n", opt)); \
	}

        REJCISHORT(CI_MRU, neg_mru, go->mru);
        REJCILONG(CI_ASYNCMAP, neg_asyncmap, go->asyncmap);
        REJCICHAP(CI_AUTHTYPE, neg_chap, PPP_CHAP, go->chap_mdtype);
        if (!go->neg_chap) {
                REJCISHORT(CI_AUTHTYPE, neg_upap, PPP_PAP);
        }
        REJCILQR(CI_QUALITY, neg_lqr, go->lqr_period);
        REJCICBCP(CI_CALLBACK, neg_cbcp, CBCP_OPT);
        REJCILONG(CI_MAGICNUMBER, neg_magicnumber, go->magicnumber);
        REJCIVOID(CI_PCOMPRESSION, neg_pcompression);
        REJCIVOID(CI_ACCOMPRESSION, neg_accompression);

        /*
        * If there are any remaining CIs, then this packet is bad.
        */
        if (len != 0)
                goto bad;
        /*
        * Now we can update state.
        */
        if (f->state != OPENED)
                *go = try;
        return 1;

bad:
        LCPDEBUG((LOG_WARNING, "lcp_rejci: received bad Reject!\n"));
        return 0;
}


/*
 * lcp_reqci - Check the peer's requested CIs and send appropriate response.
 *
 * Returns: CONFACK, CONFNAK or CONFREJ and input packet modified
 * appropriately.  If reject_if_disagree is non-zero, doesn't return
 * CONFNAK; returns CONFREJ if it can't return CONFACK.
 */
static int lcp_reqci(fsm *f,
                     u_char *inp,		/* Requested CIs */
                     int *lenp,			/* Length of requested CIs */
                     int reject_if_disagree)
{
        lcp_options *go = &lcp_gotoptions[f->unit];
        lcp_options *ho = &lcp_hisoptions[f->unit];
        lcp_options *ao = &lcp_allowoptions[f->unit];
        u_char *cip, *next;			/* Pointer to current and next CIs */
        int cilen, citype, cichar;	/* Parsed len, type, char value */
        u_short cishort;			/* Parsed short value */
        u32_t cilong;			/* Parse long value */
        int rc = CONFACK;			/* Final packet return code */
        int orc;					/* Individual option return code */
        u_char *p;					/* Pointer to next char to parse */
        u_char *rejp;				/* Pointer to next char in reject frame */
        u_char *nakp;				/* Pointer to next char in Nak frame */
        int l = *lenp;				/* Length left */
#if TRACELCP > 0
        char traceBuf[80];
        int traceNdx = 0;
#endif

        /*
         * Reset all his options.
         */
        BZERO(ho, sizeof(*ho));

        /*
         * Process all his options.
         */
        next = inp;
        nakp = nak_buffer;
        rejp = inp;
        while (l) {
                orc = CONFACK;			/* Assume success */
                cip = p = next;			/* Remember begining of CI */
                if (l < 2 ||			/* Not enough data for CI header or */
                                p[1] < 2 ||			/*  CI length too small or */
                                p[1] > l) {			/*  CI length too big? */
                        LCPDEBUG((LOG_WARNING, "lcp_reqci: bad CI length!\n"));
                        orc = CONFREJ;		/* Reject bad CI */
                        cilen = l;			/* Reject till end of packet */
                        l = 0;			/* Don't loop again */
                        citype = 0;
                        goto endswitch;
                }
                GETCHAR(citype, p);		/* Parse CI type */
                GETCHAR(cilen, p);		/* Parse CI length */
                l -= cilen;			/* Adjust remaining length */
                next += cilen;			/* Step to next CI */

                switch (citype) {		/* Check CI type */
                case CI_MRU:
                        if (!ao->neg_mru) {		/* Allow option? */
                                LCPDEBUG((LOG_INFO, "lcp_reqci: Reject MRU - not allowed\n"));
                                orc = CONFREJ;		/* Reject CI */
                                break;
                        } else if (cilen != CILEN_SHORT) {	/* Check CI length */
                                LCPDEBUG((LOG_INFO, "lcp_reqci: Reject MRU - bad length\n"));
                                orc = CONFREJ;		/* Reject CI */
                                break;
                        }
                        GETSHORT(cishort, p);	/* Parse MRU */

                        /*
                         * He must be able to receive at least our minimum.
                         * No need to check a maximum.  If he sends a large number,
                         * we'll just ignore it.
                         */
                        if (cishort < PPP_MINMRU) {
                                LCPDEBUG((LOG_INFO, "lcp_reqci: Nak - MRU too small\n"));
                                orc = CONFNAK;		/* Nak CI */
                                PUTCHAR(CI_MRU, nakp);
                                PUTCHAR(CILEN_SHORT, nakp);
                                PUTSHORT(PPP_MINMRU, nakp);	/* Give him a hint */
                                break;
                        }
                        ho->neg_mru = 1;		/* Remember he sent MRU */
                        ho->mru = cishort;		/* And remember value */
#if TRACELCP > 0
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " MRU %d", cishort);
                        traceNdx = strlen(traceBuf);
#endif
                        break;

                case CI_ASYNCMAP:
                        if (!ao->neg_asyncmap) {
                                LCPDEBUG((LOG_INFO, "lcp_reqci: Reject ASYNCMAP not allowed\n"));
                                orc = CONFREJ;
                                break;
                        } else if (cilen != CILEN_LONG) {
                                LCPDEBUG((LOG_INFO, "lcp_reqci: Reject ASYNCMAP bad length\n"));
                                orc = CONFREJ;
                                break;
                        }
                        GETLONG(cilong, p);

                        /*
                         * Asyncmap must have set at least the bits
                         * which are set in lcp_allowoptions[unit].asyncmap.
                         */
                        if ((ao->asyncmap & ~cilong) != 0) {
                                LCPDEBUG((LOG_INFO, "lcp_reqci: Nak ASYNCMAP %lX missing %lX\n",
                                          cilong, ao->asyncmap));
                                orc = CONFNAK;
                                PUTCHAR(CI_ASYNCMAP, nakp);
                                PUTCHAR(CILEN_LONG, nakp);
                                PUTLONG(ao->asyncmap | cilong, nakp);
                                break;
                        }
                        ho->neg_asyncmap = 1;
                        ho->asyncmap = cilong;
#if TRACELCP > 0
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " ASYNCMAP=%lX", cilong);
                        traceNdx = strlen(traceBuf);
#endif
                        break;

                case CI_AUTHTYPE:
                        if (cilen < CILEN_SHORT) {
                                LCPDEBUG((LOG_INFO, "lcp_reqci: Reject AUTHTYPE missing arg\n"));
                                orc = CONFREJ;
                                break;
                        } else if (!(ao->neg_upap || ao->neg_chap)) {
                                /*
                                 * Reject the option if we're not willing to authenticate.
                                 */
                                LCPDEBUG((LOG_INFO, "lcp_reqci: Reject AUTHTYPE not allowed\n"));
                                orc = CONFREJ;
                                break;
                        }
                        GETSHORT(cishort, p);

                        /*
                         * Authtype must be UPAP or CHAP.
                         *
                         * Note: if both ao->neg_upap and ao->neg_chap are set,
                         * and the peer sends a Configure-Request with two
                         * authenticate-protocol requests, one for CHAP and one
                         * for UPAP, then we will reject the second request.
                         * Whether we end up doing CHAP or UPAP depends then on
                         * the ordering of the CIs in the peer's Configure-Request.
                         */

                        if (cishort == PPP_PAP) {
                                if (ho->neg_chap) {	/* we've already accepted CHAP */
                                        LCPDEBUG((LOG_WARNING, "lcp_reqci: Reject AUTHTYPE PAP already accepted\n"));
                                        orc = CONFREJ;
                                        break;
                                } else if (cilen != CILEN_SHORT) {
                                        LCPDEBUG((LOG_WARNING, "lcp_reqci: Reject AUTHTYPE PAP bad len\n"));
                                        orc = CONFREJ;
                                        break;
                                }
                                if (!ao->neg_upap) {	/* we don't want to do PAP */
                                        LCPDEBUG((LOG_WARNING, "lcp_reqci: Nak AUTHTYPE PAP not allowed\n"));
                                        orc = CONFNAK;	/* NAK it and suggest CHAP */
                                        PUTCHAR(CI_AUTHTYPE, nakp);
                                        PUTCHAR(CILEN_CHAP, nakp);
                                        PUTSHORT(PPP_CHAP, nakp);
                                        PUTCHAR(ao->chap_mdtype, nakp);
                                        break;
                                }
                                ho->neg_upap = 1;
#if TRACELCP > 0
                                snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " PAP (%X)", cishort);
                                traceNdx = strlen(traceBuf);
#endif
                                break;
                        }
                        if (cishort == PPP_CHAP) {
                                if (ho->neg_upap) {	/* we've already accepted PAP */
                                        LCPDEBUG((LOG_WARNING, "lcp_reqci: Reject AUTHTYPE CHAP accepted PAP\n"));
                                        orc = CONFREJ;
                                        break;
                                } else if (cilen != CILEN_CHAP) {
                                        LCPDEBUG((LOG_WARNING, "lcp_reqci: Reject AUTHTYPE CHAP bad len\n"));
                                        orc = CONFREJ;
                                        break;
                                }
                                if (!ao->neg_chap) {	/* we don't want to do CHAP */
                                        LCPDEBUG((LOG_WARNING, "lcp_reqci: Nak AUTHTYPE CHAP not allowed\n"));
                                        orc = CONFNAK;	/* NAK it and suggest PAP */
                                        PUTCHAR(CI_AUTHTYPE, nakp);
                                        PUTCHAR(CILEN_SHORT, nakp);
                                        PUTSHORT(PPP_PAP, nakp);
                                        break;
                                }
                                GETCHAR(cichar, p);	/* get digest type*/
                                if (cichar != CHAP_DIGEST_MD5
#ifdef CHAPMS
                                                && cichar != CHAP_MICROSOFT
#endif
                                   ) {
                                        LCPDEBUG((LOG_WARNING, "lcp_reqci: Nak AUTHTYPE CHAP digest=%d\n", cichar));
                                        orc = CONFNAK;
                                        PUTCHAR(CI_AUTHTYPE, nakp);
                                        PUTCHAR(CILEN_CHAP, nakp);
                                        PUTSHORT(PPP_CHAP, nakp);
                                        PUTCHAR(ao->chap_mdtype, nakp);
                                        break;
                                }
#if TRACELCP > 0
                                snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CHAP %X,%d", cishort, cichar);
                                traceNdx = strlen(traceBuf);
#endif
                                ho->chap_mdtype = cichar; /* save md type */
                                ho->neg_chap = 1;
                                break;
                        }

                        /*
                         * We don't recognize the protocol they're asking for.
                         * Nak it with something we're willing to do.
                         * (At this point we know ao->neg_upap || ao->neg_chap.)
                         */
                        orc = CONFNAK;
                        PUTCHAR(CI_AUTHTYPE, nakp);
                        if (ao->neg_chap) {
                                LCPDEBUG((LOG_WARNING, "lcp_reqci: Nak AUTHTYPE %d req CHAP\n", cishort));
                                PUTCHAR(CILEN_CHAP, nakp);
                                PUTSHORT(PPP_CHAP, nakp);
                                PUTCHAR(ao->chap_mdtype, nakp);
                        } else {
                                LCPDEBUG((LOG_WARNING, "lcp_reqci: Nak AUTHTYPE %d req PAP\n", cishort));
                                PUTCHAR(CILEN_SHORT, nakp);
                                PUTSHORT(PPP_PAP, nakp);
                        }
                        break;

                case CI_QUALITY:
                        GETSHORT(cishort, p);
                        GETLONG(cilong, p);
#if TRACELCP > 0
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " QUALITY (%x %x)", cishort, (unsigned int) cilong);
                        traceNdx = strlen(traceBuf);
#endif

                        if (!ao->neg_lqr ||
                                        cilen != CILEN_LQR) {
                                orc = CONFREJ;
                                break;
                        }

                        /*
                         * Check the protocol and the reporting period.
                         * XXX When should we Nak this, and what with?
                         */
                        if (cishort != PPP_LQR) {
                                orc = CONFNAK;
                                PUTCHAR(CI_QUALITY, nakp);
                                PUTCHAR(CILEN_LQR, nakp);
                                PUTSHORT(PPP_LQR, nakp);
                                PUTLONG(ao->lqr_period, nakp);
                                break;
                        }
                        break;

                case CI_MAGICNUMBER:
                        if (!(ao->neg_magicnumber || go->neg_magicnumber) ||
                                        cilen != CILEN_LONG) {
                                orc = CONFREJ;
                                break;
                        }
                        GETLONG(cilong, p);
#if TRACELCP > 0
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " MAGICNUMBER (%lX)", cilong);
                        traceNdx = strlen(traceBuf);
#endif

                        /*
                         * He must have a different magic number.
                         */
                        if (go->neg_magicnumber &&
                                        cilong == go->magicnumber) {
                                cilong = magic();	/* Don't put magic() inside macro! */
                                orc = CONFNAK;
                                PUTCHAR(CI_MAGICNUMBER, nakp);
                                PUTCHAR(CILEN_LONG, nakp);
                                PUTLONG(cilong, nakp);
                                break;
                        }
                        ho->neg_magicnumber = 1;
                        ho->magicnumber = cilong;
                        break;


                case CI_PCOMPRESSION:
#if TRACELCP > 0
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " PCOMPRESSION");
                        traceNdx = strlen(traceBuf);
#endif
                        if (!ao->neg_pcompression ||
                                        cilen != CILEN_VOID) {
                                orc = CONFREJ;
                                break;
                        }
                        ho->neg_pcompression = 1;
                        break;

                case CI_ACCOMPRESSION:
#if TRACELCP > 0
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " ACCOMPRESSION");
                        traceNdx = strlen(traceBuf);
#endif
                        if (!ao->neg_accompression ||
                                        cilen != CILEN_VOID) {
                                orc = CONFREJ;
                                break;
                        }
                        ho->neg_accompression = 1;
                        break;

                case CI_MRRU:
#if TRACELCP > 0
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CI_MRRU");
                        traceNdx = strlen(traceBuf);
#endif
                        orc = CONFREJ;
                        break;

                case CI_SSNHF:
#if TRACELCP > 0
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CI_SSNHF");
                        traceNdx = strlen(traceBuf);
#endif
                        orc = CONFREJ;
                        break;

                case CI_EPDISC:
#if TRACELCP > 0
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " CI_EPDISC");
                        traceNdx = strlen(traceBuf);
#endif
                        orc = CONFREJ;
                        break;

                default:
#if TRACELCP
                        snprintf(&traceBuf[traceNdx], sizeof(traceBuf), " unknown %d", citype);
                        traceNdx = strlen(traceBuf);
#endif
                        orc = CONFREJ;
                        break;
                }

endswitch:
#if TRACELCP
                if (traceNdx >= 80 - 32) {
                        LCPDEBUG((LOG_INFO, "lcp_reqci: rcvd%s\n", traceBuf));
                        traceNdx = 0;
                }
#endif
                if (orc == CONFACK &&		/* Good CI */
                                rc != CONFACK)		/*  but prior CI wasnt? */
                        continue;			/* Don't send this one */

                if (orc == CONFNAK) {		/* Nak this CI? */
                        if (reject_if_disagree	/* Getting fed up with sending NAKs? */
                                        && citype != CI_MAGICNUMBER) {
                                orc = CONFREJ;		/* Get tough if so */
                        } else {
                                if (rc == CONFREJ)	/* Rejecting prior CI? */
                                        continue;		/* Don't send this one */
                                rc = CONFNAK;
                        }
                }
                if (orc == CONFREJ) {		/* Reject this CI */
                        rc = CONFREJ;
                        if (cip != rejp)		/* Need to move rejected CI? */
                                BCOPY(cip, rejp, cilen); /* Move it */
                        INCPTR(cilen, rejp);	/* Update output pointer */
                }
        }

        /*
         * If we wanted to send additional NAKs (for unsent CIs), the
         * code would go here.  The extra NAKs would go at *nakp.
         * At present there are no cases where we want to ask the
         * peer to negotiate an option.
         */

        switch (rc) {
        case CONFACK:
                *lenp = (int)(next - inp);
                break;
        case CONFNAK:
                /*
                 * Copy the Nak'd options from the nak_buffer to the caller's buffer.
                 */
                *lenp = (int)(nakp - nak_buffer);
                BCOPY(nak_buffer, inp, *lenp);
                break;
        case CONFREJ:
                *lenp = (int)(rejp - inp);
                break;
        }

#if TRACELCP > 0
        if (traceNdx > 0) {
                LCPDEBUG((LOG_INFO, "lcp_reqci: %s\n", traceBuf));
        }
#endif
        LCPDEBUG((LOG_INFO, "lcp_reqci: returning CONF%s.\n", CODENAME(rc)));
        return (rc);			/* Return final code */
}


/*
 * lcp_up - LCP has come UP.
 */
static void lcp_up(fsm *f)
{
        lcp_options *wo = &lcp_wantoptions[f->unit];
        lcp_options *ho = &lcp_hisoptions[f->unit];
        lcp_options *go = &lcp_gotoptions[f->unit];
        lcp_options *ao = &lcp_allowoptions[f->unit];

        if (!go->neg_magicnumber)
                go->magicnumber = 0;
        if (!ho->neg_magicnumber)
                ho->magicnumber = 0;

        /*
        * Set our MTU to the smaller of the MTU we wanted and
        * the MRU our peer wanted.  If we negotiated an MRU,
        * set our MRU to the larger of value we wanted and
        * the value we got in the negotiation.
        */
        ppp_send_config(f->unit, LWIP_MIN(ao->mru, (ho->neg_mru? ho->mru: PPP_MRU)),
                        (ho->neg_asyncmap? ho->asyncmap: 0xffffffffl),
                        ho->neg_pcompression, ho->neg_accompression);
        /*
        * If the asyncmap hasn't been negotiated, we really should
        * set the receive asyncmap to ffffffff, but we set it to 0
        * for backwards contemptibility.
        */
        ppp_recv_config(f->unit, (go->neg_mru? LWIP_MAX(wo->mru, go->mru): PPP_MRU),
                        (go->neg_asyncmap? go->asyncmap: 0x00000000),
                        go->neg_pcompression, go->neg_accompression);

        if (ho->neg_mru)
                peer_mru[f->unit] = ho->mru;

        lcp_echo_lowerup(f->unit);  /* Enable echo messages */

        link_established(f->unit);
}


/*
 * lcp_down - LCP has gone DOWN.
 *
 * Alert other protocols.
 */
static void lcp_down(fsm *f)
{
        lcp_options *go = &lcp_gotoptions[f->unit];

        lcp_echo_lowerdown(f->unit);

        link_down(f->unit);

        ppp_send_config(f->unit, PPP_MRU, 0xffffffffl, 0, 0);
        ppp_recv_config(f->unit, PPP_MRU,
                        (go->neg_asyncmap? go->asyncmap: 0x00000000),
                        go->neg_pcompression, go->neg_accompression);
        peer_mru[f->unit] = PPP_MRU;
}


/*
 * lcp_starting - LCP needs the lower layer up.
 */
static void lcp_starting(fsm *f)
{
        link_required(f->unit);
}


/*
 * lcp_finished - LCP has finished with the lower layer.
 */
static void lcp_finished(fsm *f)
{
        link_terminated(f->unit);
}


#if 0
/*
 * print_string - print a readable representation of a string using
 * printer.
 */
static void print_string(
        char *p,
        int len,
        void (*printer) (void *, char *, ...),
        void *arg
)
{
        int c;

        printer(arg, "\"");
        for (; len > 0; --len) {
                c = *p++;
                if (' ' <= c && c <= '~') {
                        if (c == '\\' || c == '"')
                                printer(arg, "\\");
                        printer(arg, "%c", c);
                } else {
                        switch (c) {
                        case '\n':
                                printer(arg, "\\n");
                                break;
                        case '\r':
                                printer(arg, "\\r");
                                break;
                        case '\t':
                                printer(arg, "\\t");
                                break;
                        default:
                                printer(arg, "\\%.3o", c);
                        }
                }
        }
        printer(arg, "\"");
}


/*
 * lcp_printpkt - print the contents of an LCP packet.
 */
static char *lcp_codenames[] =
        {
                "ConfReq", "ConfAck", "ConfNak", "ConfRej",
                "TermReq", "TermAck", "CodeRej", "ProtRej",
                "EchoReq", "EchoRep", "DiscReq"
        };

static int lcp_printpkt(
        u_char *p,
        int plen,
        void (*printer) (void *, char *, ...),
        void *arg
)
{
        int code, id, len, olen;
        u_char *pstart, *optend;
        u_short cishort;
        u32_t cilong;

        if (plen < HEADERLEN)
                return 0;
        pstart = p;
        GETCHAR(code, p);
        GETCHAR(id, p);
        GETSHORT(len, p);
        if (len < HEADERLEN || len > plen)
                return 0;

        if (code >= 1 && code <= sizeof(lcp_codenames) / sizeof(char *))
                printer(arg, " %s", lcp_codenames[code-1]);
        else
                printer(arg, " code=0x%x", code);
        printer(arg, " id=0x%x", id);
        len -= HEADERLEN;
        switch (code) {
        case CONFREQ:
        case CONFACK:
        case CONFNAK:
        case CONFREJ:
                /* print option list */
                while (len >= 2) {
                        GETCHAR(code, p);
                        GETCHAR(olen, p);
                        p -= 2;
                        if (olen < 2 || olen > len) {
                                break;
                        }
                        printer(arg, " <");
                        len -= olen;
                        optend = p + olen;
                        switch (code) {
                        case CI_MRU:
                                if (olen == CILEN_SHORT) {
                                        p += 2;
                                        GETSHORT(cishort, p);
                                        printer(arg, "mru %d", cishort);
                                }
                                break;
                        case CI_ASYNCMAP:
                                if (olen == CILEN_LONG) {
                                        p += 2;
                                        GETLONG(cilong, p);
                                        printer(arg, "asyncmap 0x%lx", cilong);
                                }
                                break;
                        case CI_AUTHTYPE:
                                if (olen >= CILEN_SHORT) {
                                        p += 2;
                                        printer(arg, "auth ");
                                        GETSHORT(cishort, p);
                                        switch (cishort) {
                                        case PPP_PAP:
                                                printer(arg, "pap");
                                                break;
                                        case PPP_CHAP:
                                                printer(arg, "chap");
                                                break;
                                        default:
                                                printer(arg, "0x%x", cishort);
                                        }
                                }
                                break;
                        case CI_QUALITY:
                                if (olen >= CILEN_SHORT) {
                                        p += 2;
                                        printer(arg, "quality ");
                                        GETSHORT(cishort, p);
                                        switch (cishort) {
                                        case PPP_LQR:
                                                printer(arg, "lqr");
                                                break;
                                        default:
                                                printer(arg, "0x%x", cishort);
                                        }
                                }
                                break;
                        case CI_CALLBACK:
                                if (olen >= CILEN_CHAR) {
                                        p += 2;
                                        printer(arg, "callback ");
                                        GETSHORT(cishort, p);
                                        switch (cishort) {
                                        case CBCP_OPT:
                                                printer(arg, "CBCP");
                                                break;
                                        default:
                                                printer(arg, "0x%x", cishort);
                                        }
                                }
                                break;
                        case CI_MAGICNUMBER:
                                if (olen == CILEN_LONG) {
                                        p += 2;
                                        GETLONG(cilong, p);
                                        printer(arg, "magic 0x%x", cilong);
                                }
                                break;
                        case CI_PCOMPRESSION:
                                if (olen == CILEN_VOID) {
                                        p += 2;
                                        printer(arg, "pcomp");
                                }
                                break;
                        case CI_ACCOMPRESSION:
                                if (olen == CILEN_VOID) {
                                        p += 2;
                                        printer(arg, "accomp");
                                }
                                break;
                        }
                        while (p < optend) {
                                GETCHAR(code, p);
                                printer(arg, " %.2x", code);
                        }
                        printer(arg, ">");
                }
                break;

        case TERMACK:
        case TERMREQ:
                if (len > 0 && *p >= ' ' && *p < 0x7f) {
                        printer(arg, " ");
                        print_string((char*)p, len, printer, arg);
                        p += len;
                        len = 0;
                }
                break;

        case ECHOREQ:
        case ECHOREP:
        case DISCREQ:
                if (len >= 4) {
                        GETLONG(cilong, p);
                        printer(arg, " magic=0x%x", cilong);
                        p += 4;
                        len -= 4;
                }
                break;
        }

        /* print the rest of the bytes in the packet */
        for (; len > 0; --len) {
                GETCHAR(code, p);
                printer(arg, " %.2x", code);
        }

        return (int)(p - pstart);
}
#endif

/*
 * Time to shut down the link because there is nothing out there.
 */

static void LcpLinkFailure (fsm *f)
{
        if (f->state == OPENED) {
                LCPDEBUG((LOG_INFO, "No response to %d echo-requests\n", lcp_echos_pending));
                LCPDEBUG((LOG_NOTICE, "Serial link appears to be disconnected.\n"));
                lcp_close(f->unit, "Peer not responding");
        }
}

/*
 * Timer expired for the LCP echo requests from this process.
 */

static void LcpEchoCheck (fsm *f)
{
        LcpSendEchoRequest (f);

        /*
         * Start the timer for the next interval.
         */
        LWIP_ASSERT("lcp_echo_timer_running == 0", lcp_echo_timer_running == 0);

        TIMEOUT (LcpEchoTimeout, f, lcp_echo_interval);
        lcp_echo_timer_running = 1;
}

/*
 * LcpEchoTimeout - Timer expired on the LCP echo
 */

static void LcpEchoTimeout (void *arg)
{
        if (lcp_echo_timer_running != 0) {
                lcp_echo_timer_running = 0;
                LcpEchoCheck ((fsm *) arg);
        }
}

/*
 * LcpEchoReply - LCP has received a reply to the echo
 */
static void lcp_received_echo_reply (fsm *f, int id, u_char *inp, int len)
{
        u32_t magic;

        (void)id;

        /* Check the magic number - don't count replies from ourselves. */
        if (len < 4) {
                LCPDEBUG((LOG_WARNING, "lcp: received short Echo-Reply, length %d\n", len));
                return;
        }
        GETLONG(magic, inp);
        if (lcp_gotoptions[f->unit].neg_magicnumber
                        && magic == lcp_gotoptions[f->unit].magicnumber) {
                LCPDEBUG((LOG_WARNING, "appear to have received our own echo-reply!\n"));
                return;
        }

        /* Reset the number of outstanding echo frames */
        lcp_echos_pending = 0;
}

/*
 * LcpSendEchoRequest - Send an echo request frame to the peer
 */

static void LcpSendEchoRequest (fsm *f)
{
        u32_t lcp_magic;
        u_char pkt[4], *pktp;

        /*
        * Detect the failure of the peer at this point.
        */
        if (lcp_echo_fails != 0) {
                if (lcp_echos_pending++ >= lcp_echo_fails) {
                        LcpLinkFailure(f);
                        lcp_echos_pending = 0;
                }
        }

        /*
        * Make and send the echo request frame.
        */
        if (f->state == OPENED) {
                lcp_magic = lcp_gotoptions[f->unit].magicnumber;
                pktp = pkt;
                PUTLONG(lcp_magic, pktp);
                fsm_sdata(f, ECHOREQ, (u_char)(lcp_echo_number++ & 0xFF), pkt, (int)(pktp - pkt));
        }
}

/*
 * lcp_echo_lowerup - Start the timer for the LCP frame
 */

static void lcp_echo_lowerup (int unit)
{
        fsm *f = &lcp_fsm[unit];

        /* Clear the parameters for generating echo frames */
        lcp_echos_pending      = 0;
        lcp_echo_number        = 0;
        lcp_echo_timer_running = 0;

        /* If a timeout interval is specified then start the timer */
        if (lcp_echo_interval != 0)
                LcpEchoCheck (f);
}

/*
 * lcp_echo_lowerdown - Stop the timer for the LCP frame
 */

static void lcp_echo_lowerdown (int unit)
{
        fsm *f = &lcp_fsm[unit];

        if (lcp_echo_timer_running != 0) {
                UNTIMEOUT (LcpEchoTimeout, f);
                lcp_echo_timer_running = 0;
        }
}

#endif /* PPP_SUPPORT */
